Effect of cryogenic chill on mechanical properties of ASTM A 494 M grade nickel based alloy metal matrix composites

An investigation in the present research was made to fabricate and evaluate the microstructure and mechanical properties of metal matrix composites developed using cryogenically cooled copper chills, consisting of ASTM A 494 M grade nickel alloy matrix and garnet particles as the reinforcement. The particle's amount added ranges from 3 wt. % to 12 wt. % in steps of 3%. A stir casting process was used to fabricate the composite. The matrix alloy was melted in a casting furnace at around 1350°C, the garnet particulates preheated to 600°C, were introduced into the molten metal alloy. When pouring melt into mould, an arrangement was made at one end of the mould by placing copper chill blocks of varying thickness brazed with MS hallow block in which liquid nitrogen was circulated simultaneously for cryogenic effect. After solidification produced composite materials thus synthesized were examined for microstructural and mechanical properties as per ASTM standards.